1. Field of the Invention
The present invention relates to a manipulator apparatus and a medical device system, and in particular to a manipulator apparatus having a plurality of joints driven efficiently in a manner dependent on a target treatment and to a medical device system which includes the manipulator apparatus.
2. Description of the Related Art
In recent years endoscopic surgery for performing various treatments inside a body cavity has become widespread. The endoscopic surgery is performed by opening an insertion hole in a body wall and inserting an endoscope and treatment instruments percutaneously into a body cavity through the insertion hole. This type of technique does not require a large dissection and is widely applied as a minimally invasive technique for cholecystectomy or resection of a part of the lung. To improve operability in this type of surgery, a master-slave type medical manipulator apparatus has been proposed.
Japanese Patent Application Laid-Open Publication No. H9-66056, for instance, discloses a medical manipulator system for use in surgery in which a plurality of medical manipulator apparatuses are used and which can cope quickly if a fault of some kind occurs in one or more of the manipulator apparatuses. The manipulator system provides a high degree of safety and operability, and allows a reduction in operating time and in the level of invasiveness to the patient.
When controlling multi-joint manipulators, inverse kinematic calculations are used to find target values for the attitude and position of manipulator distal end. In other words, when a trajectory plan is provided, inverse kinematic calculations are used to calculate joint angle trajectories for each joint. When, in the calculation of joint angle trajectories, the number of joints to be driven is large, overall driving error increases due to the compounding of errors at each joint. To deal with this problem, Japanese Patent Application Laid-Open Publication No. H3-12709 discloses a method which makes use of fuzzy inference to calculate the joint angle trajectories which allow the target values to be reached with the minimum number of driven joints.
In one type of endoscopic surgery even less invasive than conventional endoscopic surgery, treatment is performed using a medical instrument provided at a distal end portion of the endoscope. However, a treatment instrument which passes through the forceps channel of the endoscope and projects from distal end portion has poor operability, and so methods which make use of a miniature manipulator to increase the number of degrees of freedom and capabilities of the treatment instrument have been considered. Although it is difficult for such a miniature manipulator which projects from the distal end portion to have a complex structure due to size constraints, high levels of accuracy and efficiency are demanded. However, with this type of miniature manipulator apparatus, it is difficult to achieve both high accuracy and high efficiency.
A medical device system which makes use of one or more highly accurate and highly efficient miniature manipulators projecting from the distal end portion is also desired.